In the manufacture of magnetic heads, for instance, it is often necessary to bond two or more pieces of ceramic material together. Magnetic ferrite, for instance, is a common core material for magnetic heads. The magnetic ferrite is bonded to supporting pieces of a non-magnetic ceramic so that the surface of the magnetic head interfacing with the magnetic media is formed from a ceramic material. The ceramic material generally provides a long lasting surface against any abrasion that may occur with contact to the magnetic media.
Diffusion bonding has not found wide usage in the interconnection of dissimilar ceramics because prior to this invention the expansion co-efficience of the dissimilar ceramics must match exactly. Glass is generally used as a bonding material for connecting dissimilar ceramics because the glass bond can accommodate a slight difference in the expansion co-efficient of the ceramics and glass bonding operates at lower temperatures. The diffusion bonding, however, is preferred since the glass bond line essentially produces a flaw at the edge surface of the bonded ceramics. This is especially true for magnetic heads where the magnetic heads must, at times, have some contact with a magnetic media. The glass bond line wears faster than the ceramic materials which can then cause the ceramic materials to chip at the bond line.